The Callisto cub is a pet dropped by Callisto. It is a much smaller version of Callisto.

When a player receives the pet, it will automatically try to appear as their follower. At the same time, a red message in the chatbox will state You have a funny feeling like you're being followed.

However, if a player receives a pet while having a follower out (for example, a cat), it will be placed into their inventory. When this occurs, the message in the chatbox will instead state You feel something weird sneaking into your backpack. If a players inventory is full and they have a follower already, they will not receive the pet.

On death, if a player loses their pet (as a follower or in your inventory) it will wander around for 30 seconds before disappearing completely.

Players can pay a one-time fee of 500,000 coins to Probita in East Ardougne to have this pet insured. Should the pet be lost while insured, it can be reclaimed for 1,000,000 coins.

This pet was originally polled along with the other boss pets in Content Poll #22. It gained 72.2% yes votes, 2.8% short of the passing threshold required. The introduction of the pet was re-polled in the Near Miss Poll, and passed by 90.3%.